Ultra short wave apparatus



the plate in the form of an aerial. The means Patented Nov. l7, 1936 "UNITED STATE ULTRA SHORT WAVE APPARATUS Walter Dallenbach, Berlin-Charlottenbnrg, Germany, assignor to N. V. Machinerieen-en Apl zaa gen Fabrieken "Meaf, Utrecht, Nether- Application March 1, 1935, Serial No. 8,989

In Germany March 8 1934 '1 Claim!- (Cl- 250- 11) s PATENT OFFICE.

lar directionto said plate.

The present invention relates to an arrangement for the directional emission or reception of ultra-short electro-magnetic waves.

For the purpose of emitting and receiving ultrashort electro-magnetic waves, arrangements are already known consisting of a tube with resonator, the latter beingcou'pled with an aerial over an energy line. In order to avoid radiation losses along the energy line, it is suitably designed as a concentric Lecher system. In connection herewith, however, it will prove dlflicult to couple a dipole aerial symmetrically with the energy line.

The present invention relates to an arrangement, in which the abovementioned difliculties have been obviated and in which the aerial has simultaneously been provided in. an advantageous manner with means for grouping or bunching the ultra-short waves. I

The arrangement in accordance with the present invention essentially consists of a conductive plate, a bar-shaped aerial projecting beyond said plate and further means for the grouping or bunching above said plate, the bar-shaped aerial being coupled through an aperture in the plate with a concentric energy line which-has been joined to the other side of the plate. The plate is suitably made to consist of metal. The outer conductor the energy line is conductively connected suitably with the plate. while the inner conductor is continued through the aperture in for grouping may also advantageously consist of bar-shaped aerials, disposed upon the plate. e. g. in form of a parabolic curve, and in a perpendicu- The arrangement is characterized by particular advantageous features, if as generator or receiver a tube is employed, containing as resonator which has been designed as a hollow, closed space, being coupled with the concentric energy line without the appearance of leakage or loss radiation. If the resonator is also designed as a concentric Lecher system, the conductors of this Lecher system may be continued directly as the conductors of the concentric energy line of appropriate surge impedance for the optimal adaptation of the tube to the aerial.

Fig. 1 shows an example of performance in elevation and in section, Fig. la representing the same example of performance in plan view.

I characterizes a metallic plate, carrying on its upper side a bar-shaped aerial 2 coupled with the tube and further bar-shaped serials I for grouping. The serials are suitably mounted ver- 55 tically on the plate and are tuned to the quarter wave length of the oscillation to be emitted or to be received. In the present example the barshaped aerials 8, serving as reflectors, have been disposed along a parabolic curve. In the focal line of parabolic reflector the bar-shaped aerial, coupled with the tube, has been provided. Below the plate has been stationed the ultra-short wave tube 4 with a built-in resonator. The cylindrical hollow space being essentially limited by the outer conductor 5 and the inner conductor 8 has been made to serve as the resonator. For the purpose of being able to excite the resonator, the medium part of the inner conductor 8 has been provided with a grid 1 which is advantageously madwto consist of bars disposed in an axial direction. In the axis of the grid a cathode 8, consisting of a hot wire, bent so as to possess the form of a hair pin, has been positioned In order to avoid leakage or loss radiation at the resonator of the tube, the lower end of the inner conductor 6 is provided with a metal plate 9, while the lower end of the outer conductor I is made to carry a flange l0, both parts being separated from each other only by a short distance and forming a condenser for the capacitative conduction of the oscillating current. The upper end of the inner conductor, as well as of the outer conductor of. the resonator, is connected with a concentric energy line I I. The inner conductor of the resonator is continued as inner conductor I! of the energy line without undergoing any change with regard to its cross section, while the outer conductor of the resonator is conductively connected by means of the flange-shaped part 18, with the outer conductor ll of the energy line of lesser diameter. The outer conductor I4 is conductively connected at the, upper endwith the metal plate, whereas the inner conductor 12 is continued as bar-shaped aerial 2 through an aperture in the plate.

For the purpose of obtaining a high vacuum in the tube the metal walls, limiting the resonator space or the cathode space of the tube, are provided at their edges with glass fusing, while the two flanges 9 and I0. formingthe short circuit condenser, have also been provided at their edge with a vacuum-tight glass fusing, the end of the energy line, finally, being provided with a glass fusing it. The hollow space, containing the cathode, of the inner conductor 8 has also been closed up at the lower endby means of a glass fusing i1, through which the heating current leads II have been made. to pass into the interior of the tube.

3 'At the edge of the plate I the radiation will then and the inner conductor 6 of the tube, the stream of'electrons, passing through the grid 'l'into the hollow space of the resonator, will reduce the damping of same or excite it so as to oscillate.

At the intermediate part of the hollow space a potential loop is formed and at the upper and lower end a potential node and a current loop respectively, so that the wave length of the oscillation being produced is equal to double the length of the resonator. Through the medium of the energy line, the aerial I can be adapted to the tube. If, owing to a small distance of the concentric conductor, the energy line is given a lowsurge impedance compared with the resonator and if its length is selected at M4 or an odd multiple thereof, a favorable and loose coupling of the aerial with the resonator will be secured. The influence of the energy line on the resonator will then approximately be identical with that of a short circuit condenser. Compared with the potentials in the resonator only inconsiderable alternating potential amplitudes, exciting the aerial, will present themselves at the upper end of the energy line. The aerial oscillates in such amanner that at the lower end a potential node is formed and a potential loop at theupper end. In connection herewith the inetal plate I serves for the purpose of capacitatively conducting the aerial current to the outer conductor of the energy line; In this case the metal plate plays the same role as the earth's surface when emitting and receiving earth-conducted long waves.

detach itself as tree radiation. In order to render the bending of the radiation round the edge l9 as smallas possible, the plate is given, in the direction of the emanating ray, considerable extension compared to the wave length.

Instead of the reflector arrangement represented in Figs. 1 and 1a, any of the directional emitter arrangements known in connection with earth-conducted long waves may be employed.

In the same way it will be possible to apply to the present case the directional emitter arrangement known in connection with aerials with free radiation, for instance, in such a manner, that instead of M2 aerials in the space, M4 aerials are disposed upon the conductive plate at a suitable distance.

what I claim is:

1. An arrangement for the directional emission and reception of ultra-short waves, comprising a level conductive plate having an aperture therein, rod antennas of the length A/i disposed on one side of said zyplate in parabolic curve and perpendicular to said liilatet-an electron tube on the other side of said plate, said electron tube being provided with a hollow space resonator limited by a concentric Lecher system of the length M2, a lead coupled with the inner and outer leads of the concentric Lecher system and forming a short circuit condenser for the resonator, an energy line of the length M4 coupled to one end of the concentric Lecher system, said energy line consisting of an inner conductor and an outer conductor concentric with said inner conductor, the outer conductor of said line at one end being connected with said plate, the inner conductor being continued through said aperture in the form of a rod antenna of the length M4 disposed at the focal point of the parabola and perpendicular to said plate.

2. An arrangement for the directional emission and reception of ultra-short waves, comprising a conductive plate having an aperture therein, a rod antenna on one side of the plate above said aperture, means on the. same side of the plate for bunching ultra-short waves, an electron tube on the other side of the plate, said electron tube being provided with a resonator, an energy line consisting of an inner conductor and an outer conductor concentric with said inner conductor, a rigid mechanical connection between one end of said energy line and the resonator, the outer conductor of the energy line being rigidly connected at the other end with the plate, the inner conductor being connected through said aperture with ,the rod antenna, all parts being connected mechanically to form a closed unit. l.

3. An arrangement as defined in claim 2 in which the means for'bun'ching the ultra-short waves is disposed along a parabolic curve.

4. An arrangement as defined in claim 2 in which there are a number of rod antennas on one side of the plate, said rod antennas being disposed along a parabolic curve,.one of said rod antennas being disposed at the focal line of the parabola directly above the aperture.

-5. An arrangement as defined in claim 2 in which the rod antenna is of the length M4.

6. An arrangement as defined in claim 2 in which the energy line is of the length M4;

'7. An arrangement as defined'in claim 2 in which the rod antenna and the energy line each are of the length M4.

WALTER DALLENBACH. 

